I think part of getting anyone to learn something is to engage their attention and usually their imagination.
Lace knitting has a very long history which I'm sure is filled with amazing information. You might find that reading up on the subject will give you lots of neat factoids to sprinkle throughout your teaching sessions which would hopefully add a new dimension to your students' understanding. I'm not suggesting a whole session on the history of lace knitting, just some pieces of that history which will connect your students to it.
As far as projects for the classes go I find that I get impatient with too much data and not enough "hands on", so after giving the bare bones basics maybe get everyone to cast on for a small or medium length project and then you can teach and they can do each step on an actual piece they're making.
Once they get some practice they'd be naturals to continue and do a class on the larger piece you designed. And then you'd have the advantage of working with "experienced" lace knitters since you've taught them yourself!
Whatever you decide, keep us info'd please and best of luck to you and your students!